The present invention comprises a new and distinct cultivar of a birch tree, botanically known as Betula papyrifera, and is hereto referred to by the cultivar name xe2x80x9cUencixe2x80x9d.
xe2x80x98Uencixe2x80x99 was discovered by the inventor in a group Betula payrifera in a provenance test plot planted in Wooster, Ohio, in 1986. xe2x80x98Uencixe2x80x99 was originated from the open pollinated cross in a birch selection/breeding program on Evergreen Nursery Company, Inc., property in Sturgeon Bay, Wis. The female parent was Betula papyrifera. The pollen parent was Betula papyrifera. xe2x80x98Uencixe2x80x99 was first noticed with a narrow, open, vigorous, upright growth habit, white semi-exfoliating bark and a very high resistance to the Bronze Birch Borer. The upright and open growth of the crown facilitates clumping of the trees. The open growth further allows for grass to grow under the tree since more sunlight can penetrate the ground. The cultivar has been asexually reproduced in Sturgeon Bay, Wis. The current propagation is by micropropation at Sturgeon Bay, Wis. Horticultural examination of selected units has demonstrated that the combination of characteristics as herein disclosed for xe2x80x98Uencixe2x80x99 are firmly fixed and retained through its successive generations of asexual reproduction. xe2x80x98Uencixe2x80x99 has been observed in Sturgeon Bay, Wis. and Wooster, Ohio, since 1986 and characteristics have been stably maintained. The cultivar reproduces true to type. The new cultivar has not been observed under all possible environmental conditions. The phenotype may vary somewhat with variations in environment such as temperature, day length and light intensity, without a change in the genotype of the cultivar. The following observations, measurements, and comparisons describe the plants grown in Sturgeon Bay, Wis. under natural field conditions which approximate those generally used in commercial growing operations.
The following traits have been repeatedly observed and are determined to be basic characterisitcs of xe2x80x98Uencixe2x80x99 which in combination distinguish this birch tree as a new and distinct cultivar:
1. Distinctive narrow, open, vigorous, upright growth habit with branching angles about 50xc2x0.
2. Bark color changes as the tree matures; from brown turning to white.
3. Semi-exfoliating bark when mature.
4. Very high resistance to the Bronze Birch Borer.
5. Fast growth rate.
The new cultivar can be compared to the nonpatented Batula papyrifera for the foregoing characteristics differ from the nonpatented variety in that the nonpatented variety has variable resistance to the Bronze Birch Borer, has a loose oval growth habit and its bark is exfoliating.